The Roach That Failed
July 25, 2004
By SAM SCHECHNER
In 1979, the police in Schenectady, N.Y., responded to a
complaint about a barking dog. When they arrived, however,
they found cockroaches streaming from the windows of a
two-family home, raining down from trees and darting into
the street. Inside, roaches had plastered every wall like
stucco and had left bites all over a 64-year-old woman and
her 24 dogs, which, it turned out, had been barking for
good reason. The swarm comprised approximately one million
German cockroaches, perhaps the largest household
infestation ever recorded.
In those days, the war on roaches seemed hopeless. The
insects were a ubiquitous fixture of kitchens and
bathrooms, basements and streets; in 1985, The Washington
Post reported that they had infiltrated the Pentagon.
Roaches were linked to the spread of infectious diseases
like salmonella poisoning and were at least partly
responsible for the rising asthma epidemic in inner cities.
It was frequently predicted, uncomfortably, that an army of
roaches would survive even a nuclear holocaust.
But in the 70's and 80's, scientists were already honing a
weapon -- new bait eventually sold as Combat and other
products -- that would change the course of the war.
Because of it, populations of German cockroaches, by far
the most common household variety, have fallen
precipitously in many urban areas. ''They were decimated,''
says Phil Koehler of the University of Florida. But could
roaches go away for good? And would it really be good
riddance if they did?
Of the more than 3,500 species within the insect order
Blattaria, only a small fraction cross paths with humans
enough to be considered pests. Some, like the enormous
American cockroach, or palmetto bug, live mostly in sewers
or dark, dank basements. But Blattella germanica, otherwise
known as the German cockroach, actually lives with us in
our own homes. ''They are an artifact of human existence,''
says Dini Miller, an entomologist at Virginia Tech. In all
likelihood, they moved in with humans in Africa, when we
first started storing our food and living indoors. ''Since
then, they have evolved with us,'' she said.
For almost as long, we have been trying to kill them and
their Blattarian relatives. The Egyptian Book of the Dead,
written more than 3,000 years ago, includes a spell
invoking the ram-headed god Khnum to banish vile
cockroaches. As the roaches spread around the world on
ships, some sailors, finding their eyelashes eaten off in
the night, ineffectually tried to kill them by burning
sulfur. By the late 19th century, people were setting traps
with molasses, and exterminators were advertising their
services in local papers.
The 20th century brought synthetic insecticides and
crack-and-crevice sprays, but nothing offered more than
temporary relief, even in wealthy urban areas. German
roaches reproduce more rapidly than other roach species,
and for almost every new chemical thrown at them, germanica
has developed widespread resistance, usually within a
decade. In the 50's, scientists thought DDT would finally
wipe them out; less than 10 years later, they told tales of
bugs swimming in vats of the stuff.
Then, around the time of the Schenectady infestation,
researchers at American Cyanamid in New Jersey stumbled
upon an idea. Casting about for other uses for an odorless,
tasteless agricultural insecticide called hydramethylnon,
they decided to try it on German roaches. The only catch
was that it needed to be ingested. So they made bait.
''The field data were very promising,'' says Jules
Silverman, a researcher who helped refine the first
hydramethylnon bait in the early 80's. ''We would find
greater than 90 to 95 percent reductions in cockroach
populations, across the country.'' Scientists, who had
first tested the concept by dipping communion wafers in the
poison, toyed with the idea of selling the wafers under the
label Last Supper. In the end, they packed better bait in
plastic pucks with the name Maxforce. (Combat, the consumer
version, came out two years later.)
It wasn't until after the bait had been on the market for a
few years that entomologists discovered why they worked so
well: even if only 20 percent of an infestation fed on
them, lethal doses would remain in their feces and
carcasses, which would be fed upon by other roaches back in
the cracks and narrow passages where they live. ''There
were no hiding places for cockroaches to escape the
insecticide,'' says Coby Schal, an urban entomologist at
North Carolina State University.
Hard data on roach populations are scarce, but evidence is
mounting that widespread adoption of bait in the 90's took
its toll. In Miami, traditionally a warm, wet roach
stronghold, the public housing authority has seen its work
orders for cockroach problems drop from thousands per year
to just a few hundred per year today. A decade-long survey
of 55 federal buildings found that cockroach complaints
between 1988 and 1999 fell by more than 93 percent. And
although roaches long generated the most income for
commercial exterminators, they have dropped down the list
to No. 3, behind ants and termites, according to the trade
magazine Pest Control.
The same pattern emerged in the consumer market as well.
Sales of off-the-shelf bait exploded in the 90's, rising to
as much as $80 million per year. Then the bottom fell out.
The market for all roach-control products -- not just bait
but also the more common roach aerosols -- began to shrink
in 1996, according to retail data cited by Clorox, which
now owns Combat. ''It appears that they may have been so
successful that they dried up the market,'' says Ken
Harris, a founder of Cannondale Associates, a marketing
By the end of 2000, Pest Control found itself running a
column titled ''Are Cockroach Baits Simply Too Effective?''
The U.S. consumer market for roach control continues to
shrink by 3 to 5 percent a year, says Derek Gordon, vice
president for marketing at Clorox. ''And if we actually
manage to drive ourselves out of business completely,
frankly we'd feel like we did the world a service.''
The respite may be short-lived, however. Some pest-control
operators argue that invasive species of ants have rushed
to fill the household niche that cockroaches left behind.
Others say that when operators turned from residual sprays
to bait, they left us increasingly exposed to bed bugs,
which have returned to suck blood at both fleabag and
five-star hotels in the last few years.
Moreover, the German roach itself may rise again. At the
National Conference on Urban Entomology in Phoenix this
May, a blockbuster symposium sported a marquee-ready title:
''The Resurrection of the German Cockroach.'' Entomologists
read papers and showed videos suggesting that while roaches
have still not developed resistance to hydramethylnon, even
after 20 years of heavy use, some have evolved to avoid
bait containing certain sugars or additives.
The findings don't foreshadow a return to Schenectady. Most
consumer bait still works; and Bayer, the chemical and
pharmaceutical giant, has unveiled a formulation that
caters to the new roaches' finicky tastes. But urban
entomologists clearly have good reason to return to the
''I'm thrilled to death they've come back,'' Dini Miller
said at the event. The roach scientists in the audience
Sam Schechner is a freelance writer in New York.